As is known to all, if an integrated circuit can be designed to have a lower power consumption, a lower packaging cost, a lower power cost, a lower cooling cost and a higher reliability will be obtained, thereby improving the competitiveness of products.
There are meanings in two aspects for reducing the power consumption of a circuit (hereafter referred to as target circuit); one aspect is to reduce the dynamic power consumption of the target circuit under the working condition, and the other aspect is to reduce the static power consumption of the target circuit under the non-working condition. The working voltage and working frequency required by the target circuit under the working condition and those under the non-working condition are different. If the working condition is further refined, the working voltage and working frequency required by the target circuit are different for different application scenarios. If the working voltages and working frequencies of the target circuit under different working conditions can be dynamically adjusted, then, when the target circuit executes simpler tasks/programs (or under non-working conditions), the working voltage and working frequency thereof will be reduced, and when the target circuit executes more complicated tasks/programs, the working voltage and working frequency thereof will be increased, so that the total power consumption of the target circuit will be reduced effectively under the premise of ensuring the original performance of the target circuit not reduced.
It is very complicated to adjust the voltage and frequency of the target circuit by the conventional system for controlling working voltage and working frequency. The conventional system mainly adopts software, especially the operating system, to analyze the task or application program to be executed, so as to acquire the working voltage and working frequency required to execute the task; the conventional system adjusts the working voltage and working frequency of the target circuit through software prior to executing the task, and the task or application program will not be executed until the voltage and frequency are adjusted to the required values. This kind of adjusting method by the conventional system mainly relies on software, and the adjusting module is divided into a plenty of independent configurations, as a result, the adjusting process is rather complicated, the adjusting time length gets longer, and the burden of the software program is increased greatly.
When adjusting the voltage and frequency of the target circuit by the conventional system for dynamically controlling working voltage and working frequency, the adjusting efficiency is lower, which is mainly reflected in that: the working voltage is increased when the target circuit is required to work at a higher frequency, or the working voltage is reduced when the target circuit is required to work at a lower frequency, wherein, the standard of increasing or reducing the working voltage is unified without differentiating the manufacturing process differences or the working environment differences of the target circuit. In fact, the target circuit under different working conditions requires different minimum voltages at the same working frequency. If the system for dynamically controlling the working voltage and working frequency does not differentiate the manufacturing process differences or the working environment differences of the target circuit, only the higher voltage can be adopted as the unified adjusting standard, as a result, the working voltage cannot be lowered as much as possible. Therefore, the conventional system for dynamically controlling working voltage and working frequency cannot realize the most optimized energy saving solution.
The conventional system for dynamically controlling the working voltage and working frequency adopts a simple and direct method when adjusting the voltage and frequency of the target circuit. In order to achieve the effect of reducing the number of adjusting configurations and reducing the burden of the software, the conventional system for dynamically controlling working voltage and working frequency normally adopts a one-step method to adjust the voltage or frequency of the target circuit, which cannot prevent the system from being impacted due to the rapid change of the voltage or frequency; as a result, the conventional system cannot leave enough buffering time for switching system status, or, the running of the target circuit has to be interrupted during buffering. Therefore, the conventional system for controlling the working voltage and working frequency is not safe and fast enough.